This invention relates in general to fuel cell systems and in particular to an apparatus and method for controlling fuel cell systems.
The control of closely coupled fuel processor & fuel cell systems presents numerous challenges. The supply of hydrogen must be balanced with the load demand to provide adequate electrical power without returning too much or too little heating capacity to the fuel processor through the form of hydrogen unconsumed by the fuel cell. When the system is to operate in a grid-attached manner, the transients of the load can be shared and their effects minimized by the grid. The sharing of load allows for longer ramp times and slower responding controls.
By contrast, mobile generators must react quickly since these generators cannot rely on the rest of the grid to share the transient, and the load changes can be a significant percentage of the rated power. The process described in accordance with the present invention is a novel method of controlling a mobile, integrated fuel processor and fuel cell system. Such mobile generators are often of low net power with a typical capacity in the range of 1 to 50 KW.